Hybrid plants 2. Reverse osmosis system. Courtesy: Bechtel Power the SWRO membranes. This pressure can range from 6.9 to 18.6 bar (100 to 270 psig) for brackish water to 38 to 83 bar for seawater applications. Today's membrane designs are capable of removing salts with very high efficiency-obtaining up to 99.8% salt rejection. POWER reviewed a utility-scale SWRO system that was recently constructed in China in the April issue: " Sub-Sea Water Treatment System Provides Reliable Supply for the Huaran Power Plant. " Table 1. Key features of CSP solar technologies. Source: Bechtel Power Max temp (C) Technology type Trough Linear Fresnel Solar tower Working fluid Synthetic oil HTF Steam Steam the water passes through the membrane, the remaining feedwater increases in salt content proportionally. This concentrated portion of the feedwater (known as the brine or the re395 270 545 ject) is discharged without passing through the membrane. A high-pressure booster pump supplies the pressure required to force the water through The primary cost of operating an SWRO system is the energy required to increase seawater pressure high enough to overcome the system osmotic pressure and force the seawater to permeate the RO membranes. The actual pressure drop across the RO membranes is only about 0.5 to 1 bar, depending on the number of elements per pressure vessel, so the RO reject stream is released at high pressure. Energy recovery devices (ERD) such as Pelton turbine wheels or pressure exchangers are used to recover the energy from the reject stream and reduce operating costs. An ERD can reduce the energy consumption of the SWRO booster pump by approximately 35% to 45%. A typical seawater reverse osmosis skid is shown in Figure 2. Do you need On-Site Scanning? Our services include: * Scanning engineering drawings * CAD/Vector Conversion * Scanning O&M manuals using High Speed scanning equipment (Which we'll leave on site if you wish!) * Scanned data corrections, taxonomy and database support We work within your existing framework and operating preferences to turn your paper information into a valuable electronic tool. Your plant data is more useable NOW! And without waiting for (or paying for) an enterprise solution. See us at Booth # 1355 Electric Power 2010 in Baltimore, May 18-20 ATLANTA ׀ NEW YORK ׀ SAN FRANCISCO ׀ INDIANAPOLIS ׀ CINCINNATI RUSSELSHEIM ׀ HYDERABAD ׀ SINGAPORE ׀ TOKYO ׀ COLOMBO ׀ VANCOUVER circle 49 on reader service card May 2010 | POWER www.powermag.com circle 50 on reader service card 105http://www.powermag.com